Age ≥65 years (hazard ratio [HR]: 2.98, 95% CI: 1.27–7.02; P = 0.012), concomitant bloodstream infection (HR: 3.53, 95% CI: 1.50–8.32; P = 0.004), fever ≥38.5 °C (HR: 3.03, 95% CI: 1.45–6.31; P = 0.003), mechanical ventilation prior to CDI (HR: 3.20, 95% CI: 1.46–7.00; P = 0.004), connective tissue disease (HR: 5.53, 95% CI: 1.39–22.00; P = 0.015), macrolide use (HR: 10.17, 95% CI: 2.25–45.93; P = 0.003) and albumin ≤2.5 mg/dL (HR: 3.94, 95% CI: 1.38–11.25; P = 0.011) were independently associated with poor prognosis in CDI patients (Table 4). Here, ALB is linked to connective tissue disorder.